The breakdown in contract talks between Boston's Tufts Medical Center physicians and Blue Cross and Blue Shield of Massachusetts has patients fretting they may not be able to see their doctors, and scrambling to come up with alternate caregivers. Tufts Medical Center and its physicians group said they had been unable to reach an agreement with Blue Cross after 11 months of talks. Without a solution, Tufts doctors will no longer accept Blue Cross members as of Feb. 1.